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California Exhaust & Muffler Laws (2026)

Info: Your vehicle needs an adequate muffler, you can't run a cutout or bypass (which routes exhaust around the muffler), vehicles under 6,000 pounds are capped at 95 decibels measured by the SAE J1169 test, and any aftermarket exhaust has to be legal under California Air Resources Board (CARB) rules (Cal. Veh. Code §§ 27150-27151, 27156).

InfoVerified Jun 19, 2026

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Official source: leginfo.legislature.ca.gov →

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Exhaust & Muffler in states bordering California

The same rule in each neighboring state LawLert has verified, from that state’s own official source.

ArizonaInfo
Your vehicle needs a working muffler. A muffler cutout or bypass (which routes exhaust around the muffler) is prohibited, and excessive fumes or smoke are barred. A violation carries a civil penalty. Arizona sets no fixed decibel limit (A.R.S. § 28-955).
Verified Jul 23, 2026 · Source: azleg.gov · Full Arizona rule →
NevadaInfo
Your vehicle needs a muffler in good working order that meets the Department's rules, and cutouts and bypasses (which route exhaust around the muffler) are banned on the highway. No fixed decibel limit is confirmed (NRS § 484D.415).
Verified Jun 19, 2026 · Source: leg.state.nv.us · Full Nevada rule →
OregonInfo
Your vehicle needs a proper exhaust. On the Department of Environmental Quality's stationary test, passenger cars built in 1976 or later are capped at 88 decibels, and cars built before 1976 at 92 decibels, measured at 25 feet (Or. Rev. Stat. § 815.250).
Verified Jun 19, 2026 · Source: oregonlegislature.gov · Full Oregon rule →

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